How does hydro power contribute with any form of pollution on land?

Hydropower is generally considered a clean energy source, but it can contribute to land pollution in several ways. The construction of dams and reservoirs can lead to habitat destruction, altering ecosystems and displacing wildlife. Additionally, the accumulation of organic matter in reservoirs can produce methane, a potent greenhouse gas, as it decomposes underwater. Furthermore, sedimentation can occur, impacting water quality and potentially leading to increased erosion and land degradation around the dam site.